NIV takes up study of Congo fever

The National Institute of Virology (NIV) has initiated a serosurvey with the Indian Council of Agricultural Research (ICAR) to understand the presence and threat of the animal tick–borne Crimean–Congo HaemorrhagicFever (CCHF) virus in different states in India.

The viral infection has affected 24 people and claimed 16 lives ever since it was first identified in humans in India in 2010. Of them, 11 confirmed cases of the virus infection and seven deaths have been reported so far, this year. There were three positive cases and two deaths, last year.

Only Rajasthan and Gujarat have reported the viral infection cases and deaths. The most recent outbreak of the viral infection was confirmed by NIVin Kariyana village,of Babara taluka in Amreli districtof Gujaraton June 23. A serosurvey screens the serum of persons at risk to determine the susceptibility to a disease.

"The alertness of the health authoritiesin Gujarat and continuous quick technical support given for detection resulted in more cases of CCHF virus infection being reported this year. Earlier, fewer cases were reported becauseof the absenceof differential diagnosis, lack of awareness among medical staff and samples not reaching our Biosafety Level 4 laboratory at NIV," senior scientist Devendra Mourya, director of NIV, told TOI on Wednesday.

Person–to–person transmission of the virus occurs through direct exposure to blood or other secretions, and instances of nosocomial transmission, a hospitalacquired infection, are well–documented.

"About 60% of the animal blood samples drawn from cattle, sheep, goats in Gujarat tested positive for CCHFV immunoglobulin G (IgG) antibodies. The disease–causing hyalomma anatolicum anatolicum tick from the bodies of these animals were also found positive. Gujarathealth authorities have taken the initiative to kill ticks in Kariyana village by spraying insecticide and monitoring each suspected patient having fever," Mourya said.

Scientist Pragya Yadav, an expert from NIV’s BSL–4 laboratory, said, "Among domestic animals, cattle, sheep, and goat play an important role in the natural cycle of the virus. CCHF virus replicates in these animals but generally causes only subclinical disease, while in humans, infections often result in severe haemorrhagic fever, with high levels of viral replication occurring in all major organs, including the liver."

According to 18th livestock census in the country 199.08 million cattle, 105.34 million buffaloes, 140.54 million goats and 71.56 million sheep contribute to the economy by various means.

"Such huge population of livestock is in close contact with the human beings. This increases the possibility of spread of this virus," Yadav said.

KEY FACTS

The infection caused by the Crimean–Congo hemorrhagic fever (CCHF) virus was first confirmed in human in India in 2010

The virus is maintained in nature predominantly in the Ixodid tick vectors, particularly ticks of the genus Hyalomma

Among domestic animals, cattle, sheep, and goat play an important role in the natural cycle of the virus. In these animals, CCHF virus replicates but generally causes only

subclinical disease, while in human infections often result in severe hemorrhagic fever (HF), with high levels of viral replication occurring in all major organs, including the liver

Animal handlers, butchers and others associated with slaughter houses and treating doctors and nursing staff are at high risk of contracting the virus infection

(SOURCE: NATIONAL INSTITUTE OF VIROLOGY, PUNE)
According to 18th livestock census in India, 199.08m cattle, 105.34m buffalo, 140.54m goat and 71.56m sheep contribute to the economy in various ways

Among domestic animals, cattle, sheep, and goat play an important role in the natural cycle of the virus. CCHF virus replicates in these animals but generally causes only subclinical disease, while in humans, infections often result in severe haemorrhagic fever, with high levels of viral replication occurring in all major organs, including the liver

Pragya Yadav | SCIENTIST , AN EXPERT FROM NIV’S BSL–4 LABORATORY

The alertness of the health authorities in Gujarat and continuous quick technical support given for detection resulted in more cases of CCHF virus infection being reported this year

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